Lens antenna array system with power optimization for improved signal quality

ABSTRACT

A lens antenna array system for wireless communication is provided that includes a transmitter having a first lens and a receiver having a second lens. The transmitter transmits a first plurality of RF signals across a plurality of near-field communication links to the receiver. Based upon a first signal quality determination at the receiver, the transmitter adjusts a plurality of gains to increase a signal quality for a second plurality of RF signals transmitted across the plurality of near-field communication links.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.63/055,109, filed Jul. 22, 2020, the contents of which are herebyincorporated by reference in their entirety.

TECHNICAL FIELD

The technology discussed below relates generally to wirelesscommunication systems, and more particularly, to a lens antenna arraysystem with power optimization for improved signal quality across aplurality of communication links.

BACKGROUND

To meet the growing demands for expanded mobile broadband connectivity,wireless communication technologies advanced from the long-termevolution (LTE) technology to a next generation new radio (NR)technology, which may also be referred to as 5th Generation (5G). Forexample, NR is designed to provide a lower latency, a higher bandwidthor a higher throughput, and a higher reliability than LTE. NR isdesigned to operate over a wide array of spectrum bands, for example,from low-frequency bands below about 1 gigahertz (GHz) and mid-frequencybands from about 1 GHz to about 6 GHz, to high-frequency bands such asmillimeter wave (mmWave) bands. Despite this wide array of spectrumbands, the supported data rates may not be sufficient forvery-high-data-rate communication.

To provide increased bandwidth to support higher data rates, 5G andfuture standards such as the 6th generation (6G) propose the use ofsub-Terahertz (e.g., 100 GHz to 300 GHz) carrier frequencies. At thesehigher frequencies, the radio frequency (RF) signal begin to propagatesimilarly to visible light. Given this similarity to light propagation,various systems have been proposed in which an antenna array is combinedwith a lens to form a lens antenna array.

BRIEF SUMMARY OF SOME EXAMPLES

In accordance with an aspect of the disclosure, a lens antenna arraysystem is provided that includes: a first processor configured toprovide a plurality of baseband input data streams; a plurality ofmodulators corresponding to the plurality of baseband input datastreams, each modulator in the plurality of modulators configured tomodulate a respective baseband input data stream from the plurality ofbaseband input data streams to produce a modulated RF signal; aplurality of power amplifiers corresponding to the plurality ofmodulators, each power amplifier configured to amplify a respectivemodulator's modulated RF signal according to a gain to produce anamplified modulated RF signal; a first lens; a plurality of transmitantennas corresponding to the plurality of power amplifiers, eachtransmit antenna in the plurality of transmit antennas being configuredto transmit the amplified modulated RF signal from a respective poweramplifier, the plurality of transmit antennas being arranged in a focalregion of the first lens; and a power controller configured to adjusteach gain so that a gain of a first subset of power amplifiers in theplurality of power amplifiers is reduced from a default gain level andso that a gain of a second subset of power amplifiers in the pluralityof power amplifiers is increased from the default gain level.

In accordance with another aspect of the disclosure, a method ofwireless communication is provided that includes: at a transmitterincluding an array of transmit antennas arranged in a focal region of atransmit lens, amplifying a plurality of first modulated RF signalsthrough a plurality of power amplifiers according to a default gain toproduce a corresponding plurality of first amplified modulated RFsignals; transmitting from each transmit antenna a respective firstamplified modulated RF signal from the plurality of first amplifiedmodulated RF signals to form a plurality of first transmitted RFsignals, each first transmitted RF signal refracting through thetransmit lens and near-field propagating to a receiver; adjusting thedefault gain for each power amplifier responsive to a first signalquality determination for the plurality of first transmitted RF signalsto form a plurality of adjusted gains; and amplifying a plurality ofsecond modulated RF signals through the plurality of power amplifiersaccording to the plurality of adjusted gains to produce a correspondingplurality of second amplified modulated RF signals.

In accordance with yet another aspect of the disclosure, a method ofwireless communication is provided that includes: in a lens antennasystem including a receiver having an array of receive antennas arrangedin a focal region of a second lens, receiving at each receive antenna afirst RF signal that near-field propagated from a transmitter to form aplurality of first received RF signals; at the receiver, forming aplurality of first signal quality determinations corresponding to theplurality of first received RF signals; and reporting the plurality offirst signal quality determinations to the transmitter.

Finally, in accordance with yet another aspect of the disclosure, amethod of wireless communication is provided that includes: in a lensantenna array system including a transmitter and a receiver, near-fieldpropagating from a transmit lens in the transmitter to the receiver aplurality of first amplified RF signals; at the transmitter, receivingfrom the receiver a signal quality determination for the plurality offirst amplified RF signals; and adjusting a plurality of gains for aplurality of power amplifiers in the transmitter responsive to thesignal quality determination.

These and other aspects of the disclosure will become more fullyunderstood upon a review of the detailed description, which follows.Other aspects, features, and embodiments of the present invention willbecome apparent to those of ordinary skill in the art, upon reviewingthe following description of specific, exemplary embodiments of thepresent invention in conjunction with the accompanying figures. Whilefeatures of the present invention may be discussed relative to certainembodiments and figures below, all embodiments of the present inventioncan include one or more of the advantageous features discussed herein.In other words, while one or more embodiments may be discussed as havingcertain advantageous features, one or more of such features may also beused in accordance with the various embodiments of the inventiondiscussed herein. In similar fashion, while exemplary embodiments may bediscussed below as device, system, or method embodiments it should beunderstood that such exemplary embodiments can be implemented in variousdevices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a lens antenna array system in which a centraltransmit antenna transmits a beam to a central receive antenna inaccordance with an aspect of the disclosure.

FIG. 1B illustrates a lens antenna array system in which an uppertransmit antenna transmits a beam to a lower receive antenna inaccordance with an aspect of the disclosure.

FIG. 1C illustrates a lens antenna array system in which a lowertransmit antenna transmits a beam to an upper receive antenna inaccordance with an aspect of the disclosure.

FIG. 2 illustrates a received power profile for a receive antenna in anarray of receive antennas for a lens antenna array system in accordancewith an aspect of the disclosure.

FIG. 3 illustrates a transmitter and receiver configuration for a lensantenna array system with on-off keying modulation in accordance with anaspect of the disclosure.

FIG. 4 illustrates the transmit/receive antenna positions for aplurality of active links and their SIR in which each active link uses adefault gain in accordance with an aspect of the disclosure.

FIG. 5 illustrates the transmit/receive antenna positions for aplurality of active links and their SIR in which each active link usesan adjusted gain (denoted below each active link) to increase overallsignal quality in accordance with an aspect of the disclosure.

FIG. 6 illustrates an example generic architecture for an access pointor a user terminal in a lens antenna array system in accordance with anaspect of the disclosure.

FIG. 7 illustrates a flowchart for a method of establishing the activedownlink and uplink links and of optimizing a gain for the active linksin a lens antenna array system in accordance with an aspect of thedisclosure.

FIG. 8 illustrates a flowchart for re-optimizing the gain of the activelinks during a connected mode of operation for a lens antenna arraysystem in accordance with an aspect of the disclosure.

FIG. 9 is a flowchart for an example method of wireless communicationincluding a lens antenna array system in accordance with an aspect ofthe disclosure.

DETAILED DESCRIPTION

Data flow in static scenarios such as in data centers tends to be verybursty. It is thus typical that a relatively large percentage of thetotal data flow occurs over a relatively small percentage of theoperating time for a computer network data flow. To accommodate such“elephant flows” of data, it is conventional to use an optical fiberlink. Data as represented by electronic signals is converted intooptical signals that propagate across the fiber from a transmitter to beconverted back into electronic form at a receiver. But once installed,an optical link requires a fixed topology. As an alternative, free-spaceoptics may be used such as through the use of micro-electro-mechanicalmirrors. But such systems are expensive and difficult to maintain.

To provide an alternative to optical links, a lens antenna array systemis disclosed that is readily reconfigured so that a transmitter and areceiver may be re-positioned yet offers the bandwidth to accommodaterelatively-large data rates (e.g., 25 to 100 Gbps). The system includesboth simplex and duplex embodiments with regard to communication betweentwo lens antenna array endpoints. In a simplex mode of operation, one ofthe endpoints is a lens antenna array transmitter whereas a second oneof the endpoints is a lens antenna array receiver. In a duplexembodiment, both endpoints function as a lens antenna array transmitterand as a lens antenna array receiver. The following discussion will bedirected to a simplex embodiment without loss of generality such thatthere is a dedicated lens antenna array transmitter endpoint and adedicated lens antenna array receiver endpoint. But since the topologyof the endpoints may be the same, the roles of such fixed endpoints arereadily reversed such that what is described as a transmitter mayinstead function as a receiver. Similarly, what is described as areceiver may instead function as a transmitter.

The lens antenna array transmitter includes an array of transmitantennas arranged in a focal region of a first lens. The lens antennaarray receiver also includes an array of receive antennas arranged in afocal region of a second lens. To obtain the desired high data rates,the data being transmitted by the lens antenna array transmitter may bedivided into multiple streams. In such embodiments, each data streamcorresponds to a single transmit antenna (or to a single correspondingsub-array of transmit antennas) in the array of transmit antennas. Moregenerally, a unique mapping is provided from a transmitting sub-array ofantennas to a corresponding receiving sub-array of antennas. Thefollowing discussion will assume that each sub-array of antennas isformed by just one antenna without loss of generality. The array oftransmit antennas are distributed across the focal region of the firstlens such that the transmitted RF signal from each transmit antenna iscollimated through the first lens to be transmitted in a correspondingangle of departure from the first lens. The positioning of each transmitantenna in the focal region of the first lens maps into a correspondingAoD-dependent focusing of the RF signal from the transmit antenna/firstlens. The second lens provides a correspondingangle-of-arrival-dependent focusing of the received RF signals ontocorresponding ones of the receive antennas.

The angle of departure may be defined with regard to a central axis ofthe first lens. About this central axis, the first lens extends in bothan azimuth direction and an elevation direction. Similarly, the array oftransmit antennas may be arranged in both the azimuth and elevationdirections about a central axis of the focal region of the first lens.An example lens antenna array system 100 is shown in FIG. 1A. A lensantenna array transmitter 101 includes a first lens 120. Some exampletransmit antennas in the array of transmit antennas include an uppertransmit antenna 105, a central transmit antenna 110, and a lowertransmit antenna 115. The transmit antennas are arranged in the focalregion of the first lens 120. As used herein, the term “lens” may referto a single lens or may instead denote a collection of multiple lenses.

The position of a transmit antenna in the focal region with respect to acentral axis 121 of the first lens 120 determines a corresponding angleof departure for a transmitted data stream from the transmit antenna.For demonstration purposes, each transmit antenna has no azimuthdisplacement with respect to the central axis 121 although such azimuthdisplacement exists for other embodiments discussed herein. Uppertransmit antenna 105 is displaced positively in the elevation directionfrom central axis 121. Central transmit antenna 110 has no elevationdisplacement with respect to central axis 121 so that central transmitantenna 110 is aligned with central axis 121. Lower transmit antenna 115is displaced negatively in the elevation direction from central axis121. For illustration purposes, only central transmit antenna 110 isactive in FIG. 1A to produce a transmitted RF signal 145 from first lens120. However, all the transmit antennas may be active in embodimentsdisclosed herein. Since central transmit antenna 110 is aligned withcentral axis 121, transmitted RF signal 145 has a zeroangle-of-departure in both the azimuth and elevation directions.

Analogous to single transmit antenna operation of FIG. 1A, it is onlyupper transmit antenna 105 that is active in FIG. 1B. Since uppertransmit antenna 105 is displaced positively in elevation from centralaxis 121, a transmitted RF signal 150 from first lens 120 has a negativeangle-of-departure in elevation due to the refraction through first lens120. Transmitted RF signal 150 has a zero angle-of-departure in azimuthsince upper transmit antenna 105 has no azimuth displacement fromcentral axis 121. As discussed with regard to FIG. 1A, all the transmitantennas may be active simultaneously but it is just upper transmitantenna 105 that is active in FIG. 1B for illustration purposes.

In FIG. 1C, it is lower transmit antenna 115 that is active. Since lowertransmit antenna 115 is displaced in the negative elevation directionfrom central axis 121, a transmitted RF signal 155 from first lens 120has a positive angle-of-departure in the elevation direction with regardto central axis 121. More generally, the displacement from central axis121 by a transmit antenna in azimuth and/or elevation translates into anangle-of-departure having the opposite signs in the azimuth and/orelevation angles. Should a transmit antenna be displaced in the focalregion from central axis 121 by a positive azimuth direction, thecorresponding angle-of-departure from first lens 120 will be in thenegative azimuth direction. Conversely, should a transmit antenna bedisplaced in the negative azimuth direction from central axis 121, thecorresponding angle-of-departure from first lens 120 will be in thepositive azimuth direction.

As shown in FIGS. 1A-1C, a lens antenna array receiver 102 includes asecond lens 125 that may have the same dimensions and construction asused for the first lens 120. Second lens 125 is aligned with the firstlens 120 such that the central axis 121 is also the central axis 121 forlens 125. An array of receive antennas is aligned along a focal regionof the second lens 125. Some example receive antennas include an upperreceive antenna 130, a central receive antenna 135, and a lower receiveantenna 140.

The position of each receive antenna in the focal region with respect tocentral axis 121 of second lens 125 determines a correspondingangle-of-arrival for a transmitted RF signal from lens antenna arraytransmitter 101 that will be focused or concentrated onto the receiveantenna. For demonstration purposes, each receive antenna has no azimuthdisplacement with respect to the central axis 121 although such azimuthdisplacement exists for other embodiments discussed herein. Upperreceive antenna 130 is displaced positively in the elevation directionfrom central axis 121. Central receive antenna 135 has no elevationdisplacement with respect to central axis 121 so that central receiveantenna 135 is aligned with central axis 121. Lower receive antenna 140is displaced negatively in the elevation direction from central axis121.

In some embodiments, the receive antennas are arranged symmetricallywith the transmit antennas. Upper receive antenna 130 thus has the samepositive elevation displacement from central axis 121 as upper transmitantenna 105. Similarly, lower receive antenna 140 has the same negativeelevation displacement from central axis 121 as does lower transmitantenna 115. Central receive antenna 135 is similarly symmetricallypositioned with no azimuth or elevation displacement for central axis121 as discussed for central transmit antenna 110. This symmetry betweenfirst lens 120, second lens 125 and the positioning of the receive andtransmit antennas results in a one-to-one mapping between each transmitantenna and a corresponding receive antenna that will receive thegreatest RF signal from the corresponding transmit antenna. For example,as shown in FIG. 1A, transmitted RF signal 145 from central transmitantenna 110 is received most strongly at central receive antenna 135.Transmitted RF signal 150 from upper transmit antenna 105 is receivedmost strongly at lower receive antenna 140 as shown in FIG. 1B.Similarly, transmitted RF signal 155 from lower transmit antenna 115 isreceived most strongly at upper receive antenna 130 as shown in FIG. 1C.

In general, receiving lens 125 provides an angle-of-arrival-dependent(AoA-dependent) focusing of a received RF signal that focuses theresulting RF energy onto a receiving antenna (or sub-array of antennas)in the array of receiving antennas. If lenses 120 and 125 are identical(or substantially identical) and the transmit antennas and the receiveantennas have the same positioning in their corresponding focal region,a one-to-one mapping occurs between each transmit antenna and acorresponding receive antenna with regard to the strongest receipt ofthe transmitted RF signal from the transmit antenna, assuming that thedistance between the receive and transmit lenses may be considered smallwith respect to D²/λ, where D is the lens diameter and is thewavelength.

This one-to-one mapping may be better appreciated with reference to FIG.2 , which illustrates the positioning of an array 200 of antennas in theelevation and azimuth directions from central axis 121. In a symmetricembodiment, an array of transmit antennas has the same positioning inthe elevation and azimuth directions as an array of receive antennas. Insuch an embodiment, it is thus arbitrary to denote array 200 as an arrayof receive antennas or an array of transmit antennas since the identicalpositioning is used for both arrays. Given this symmetry, the positionof a transmit antenna having a displacement in elevation and azimuthfrom central axis 121 maps into a receiving antenna with the oppositedisplacement in both azimuth and elevation. For example, a transmitantenna 220 has a negative displacement in azimuth and a positivedisplacement in elevation from central axis 121. A received RF signalfrom such a transmit antenna is thus focused onto a receive antenna 210with the opposite but same magnitude of azimuth and elevationdisplacements from central axis 121. The power of the received RF signalis strongest at receive antenna 210 and drops off with respect to adisplacement from a center of receive antenna 210. For example, thereceived signal power on a curve 205 that is relatively displaced fromthe center of receive antenna 210 is relatively weak compared to thereceived signal power on a curve 215 that is closer to the center ofreceive antenna. A similar one-to-one mapping exists between a transmitantenna 235 to a receive antenna 240. Each antenna has a mirror imageantenna about central axis 121. Given this mirror image, a positiveelevation displacement becomes a negative elevation displacement of thesame magnitude. Conversely, a negative elevation displacement becomes apositive elevation displacement of the same magnitude. Similarly, apositive azimuth displacement becomes a negative azimuth displacementwhereas a negative azimuth displacement becomes a positive azimuthdisplacement of the same magnitude. For example, a transmit antenna 225maps to a receive antenna 230. Similarly, a transmit antenna 245 maps toa receive antenna 250.

Given this one-to-one antenna mapping, an array of N transmit antennascan uniquely transmit N RF signals to N corresponding receive antennas,N being a positive integer. More generally, the mapping may be from onesub-array of transmit antennas to a corresponding sub-array of receiveantennas. In an implementation in which N is 25 and the data rate foreach one-to-one antenna link is 4 Gbs, the system data rate is 4*25=100Gps.

Referring again to FIGS. 1A-1C, the received signal power is onelimiting factor in increasing the data rate despite the advantage ofsupporting N separate RF signals. To significantly improve the receivedsignal power, the separation between first lens 120 and second lens 125is such that the RF signal propagation between the two lenses occurs inthe near-field regime. With regard to establishing near-fieldpropagation, note that an antenna such as one of the receive antennas orof the transmit antennas will typically have a dimension on the order ofa wavelength for the RF signal. For example, the receive and transmitantennas may be patch antennas or dipole antennas. The near-fieldpropagation regime from such wavelength-sized antennas is severalwavelengths. The wavelength of a 300 GHz RF signal is approximately 1mm. If a wavelength-sized transmit antenna is separated by acorresponding wavelength-sized receive antenna by more than severalmillimeters, the resulting RF signal propagation occurs in the far-fieldregime. In contrast, the far-field for a lens antenna array isproportional to two times the square of the lens diameter divided by thewavelength. For example, suppose each lens has a diameter of 10 cm. Theresulting far-field regime then doesn't start until the lenses areseparated by 20 m for operation at 300 GHz. In general, the near-fieldseparation between the lenses depends upon the lens diameter and theoperating wavelength. Advantageously, an R² propagation loss (R beingthe separation between lenses) does not substantially occur until theseparation R is large enough to invoke far-field propagation. With theseparation R being less than this far-field threshold, the energy of thetransmitted RF signal is effectively contained within a cylinder thatextends from the perimeter of first lens 120 to a perimeter of secondlens 125 as shown in FIGS. 1A, 1B, and 1C for RF transmitted signals145, 150 and 155, respectively. The near-field propagation of the RFtransmitted signals is thus effectively contained in a waveguide thatextends from first lens 120 to second lens 125.

High data rates are achieved by splitting source data to be transmittedinto multiple data streams that are transmitted in parallel. Uponrecovery at the receiver, the multiple data streams may then beserialized to recover the source data. In a one-to-one embodiment, thenumber of data streams transmitted in parallel equals the number of thetransmit antennas. The modulation and coding scheme (MCS) for each datastream will now be discussed. Note that a high-level MCS is affected bythe relatively large phase noise (jitter) that exists for RF signalingat high frequencies such as in the sub-THz bandwidth from 100 to 300GHz. The bandwidth for each data stream is also an issue. The bandwidthis a function of the data rate in each data stream. As the bandwidth(and hence the individual link data rate) increases, analog-to-digitalconversion for each data link in lens antenna array receiver 102 becomesmore problematic. In addition, the use of in-phase and quadrature-phasesignaling for each data link leads to increased power consumption.Furthermore, the use of frequency transform techniques such as a fastFourier transform is also problematic as the data rate is increased. Inlight of these factors, a particularly advantageous MCS is the use ofon-off keying. In on-off keying, an RF signal (for example, a sinusoid)is either transmitted (ON) or not transmitted (OFF) in sequentialsymbols. For example, in a first binary symbol the RF signal may betransmitted but in a subsequent second binary symbol no RF signal istransmitted. Depending upon the binary convention, the resulting digitalword represented by the two symbols is either 10 or 01. Each additionalbinary symbol adds another bit to the transmitted signal.

The length of each symbol may be varied in alternative embodiments butin one embodiment the symbol length may be 10 periods of the operatingfrequency. The symbol length will thus typically be shorter as theoperating frequency is increased due to the resulting shorter period forthe RF oscillation. An example lens antenna array 300 with on-off keying(OOK) modulation is shown in FIG. 3 . There are N baseband input datastreams ranging from a baseband input data stream 0 (Data In 0) to abaseband input data stream N−1 (Data In N−1). Each baseband input datastream drives a mixer 310 in a corresponding OOK modulator 305. Anoscillator such as a voltage-controlled oscillator (VCO) 325 generatesan RF signal at the desired carrier frequency for driving each mixer310. Alternatively, each OOK modulator 305 (or subset of OOK modulators305) may be driven by its own corresponding VCO. The OOK-modulated RFsignal from each mixer 310 is amplified by a corresponding poweramplifier 320. As will be explained further herein, a gain for eachpower amplifier 320 may be controlled by a gain controller 330. Eachpower amplifier 320 drives a corresponding transmit antenna 315 (orsub-array of transmit antennas 315). Each transmit antenna 315 thustransmits an RF data stream that results from the OOK modulation of theRF signal resulting from the upconverting to RF of the correspondingbaseband input data stream. Each baseband input data stream is a binaryinput data stream consisting of binary zero's and binary ones. When abinary one drives a corresponding mixer 310, the on portion of the OOKmodulation is produced whereas a binary zero produces the off portion ofthe OOK modulation. This convention may be reversed in alternativeembodiments such that a binary zero produces the on portion whereas abinary one produces the off portion.

If lens antenna array system 300 has a one-to-one mapping betweentransmit antennas 315 and a corresponding set of receive antennas 335,each receive antenna 335 receives a corresponding OOK-modulated RFsignal and drives a corresponding low-noise amplifier 340 accordingly.An envelope detector 345 is associated with each low-noise amplifier 340to envelope detect the resulting amplified OOK-modulated received RFsignal to produce a baseband output data stream. Since there are Nenvelope detectors 345, there are N baseband output data streams rangingfrom a zeroth baseband output data stream (Data Out 0) to an (N−1)thbaseband output data stream (Data Out N−1). The envelope detection isbinary in that either an envelope is detected (the “on” of the OOKmodulation) to produce a binary 1 output in the corresponding basebandoutput data stream or no signal (the “off” of the OOK modulation) isdetected to produce a binary zero in the same baseband output datastream. Alternatively, an active-low convention may be used by eachenvelope detector 345 such that the detection of an envelope produces abinary zero and the detection of the lack of an envelope produces abinary one.

Although the near-field RF propagation advantageously reduces thepropagation loss, the one-to-one mapping from a transmit antenna to areceive antenna is not perfect such that some RF energy from thetransmit antenna is received by other receive antennas besides the onetargeted by the antenna mapping. The resulting interference at otherreceive antennas may be a limiting factor in increasing the overall datarate for the lens antenna array systems disclosed herein. Theinterference may be reduced by limiting the number of transmit antennasand receive antennas that are distributed across the focal region oftheir respective lenses. But reducing the number of antennas thenreduces the number of independent data streams that can be transmitted.

With regard to the number of antennas, array 200 of FIG. 2 has 37antennas (N=37). As noted earlier for an embodiment with symmetrictransmit and receive antenna positioning, it is arbitrary to denotearray 200 as either a receive or a transmit array. The followingdiscussion will consider array 200 as representing both arrays. Eachantenna may be positioned in increments of azimuth and elevationdisplacement as measured in some multiple of the wavelength. In oneembodiment, this inter-element spacing may be 1.8 times the wavelength,but this may be varied in alternative embodiments. If each lens diameteris 150 mm, the focal length is 151 mm, the inter-element spacing is1.8*λ, and the range separation R is 3 meters for a lens antenna arraysystem having transmit and receive arrays arranged as shown for array200 with an operating frequency of 300 GHz, the signal-to-interferenceratio (SIR) at each receive antenna will depend upon the gain for eachpower amplifier 320 of FIG. 3 . For example, if the gain is equal to adefault level for each power amplifier 320 and the operating parametersare as just discussed, it may be shown that the SIR will vary widelyacross the various receive antennas in array 200. In particular, acentral-most antenna 255 will receive its corresponding RF signal withthe highest SIR (e.g, in excess of 11 dB). Other centrally-locatedantennas such as antenna 210 may receive RF signals with similarly-highSIRs. Conversely, the received RF signals for antennas 235, 225, 245,250, 230, and 240 at the outskirts of array 200 have much lower SIRs(e.g. approximately −0.3 dB). The one-to-one links with a high SIR (e.g,greater than 10 dB) could employ a higher order modulation and codingscheme (MCS) than OOK such as quadrature phase-shift keying. But suchrelatively high-order MCS cannot be employed for the links withrelatively-low SIR. In addition, the use of higher-order MCS complicatesthe design. To achieve a suitable SIR for each antenna using alower-order MCS such as OOK, gain controller 330 may boost the gain forthose links with relatively-low SIR and decrease the gain for the linkswith higher SIR. For example, suppose that the gain for the poweramplifier 320 amplifying the RF signal that is transmitted tocentral-most antenna 255 is reduced by approximately 11 dB. Lower levelsof gain reduction may then be employed as the receive antenna positionbecomes less central in array 200. This gain reduction may thentransition to a gain increase for antennas at the outer perimeter ofarray 200. For example, the gain for the transmit antennas immediatelyadjacent to central-most antenna 255 may be reduced by approximately 10dB. Conversely, the gain to the outlying antennas at the vertices of thearray perimeter such as antennas 225, 230, 235, 240, 245, and 250 may beincreased by approximately 6 dB. This results in a sufficient SIR ateach of the N links in array 200.

The resulting gain adjustment for SIR maximization across array 200 maybe better appreciated with reference to FIG. 4 and FIG. 5 . FIG. 4illustrates the SIR for each one-to-one antenna link having the samedefault gain in the embodiment as discussed above with the 1.8*λ antennaspacing. In general, an SIR of approximately 3 dB or greater may providea sufficient bit error rate for OOK modulation. All the links have asufficient SIR except those at the vertices of the array perimetercorresponding to antennas 225, 230, 235, 240, 245, and 250 of FIG. 2 .The SIR at those antenna locations is just −0.27 dB. Thus, without anygain optimization, only 31 of the 37 links are operative in the sense ofproviding a sufficient bit error rate as limited by the correspondingSIR for the link. The result after gain optimization is shown in FIG. 5. At each antenna position, the upper number is the SIR that resultsfrom the gain adjustment by the lower number at the antenna position.The link for the central-most antenna location has a gain reduction of11.61 dB. The links for the antenna locations immediately surroundingthe central-most position in the array have a gain reduction ofapproximately 10 dB. This gain reduction reduces for the links at moreremote locations from the central-most position in the array and eventransitions to a gain increase of approximately 6 dB for the links atthe antenna locations 225, 230, 235, 240, 245, and 250 of FIG. 2 . Notethat each link has an SIR above 4 dB so that all 37 links may be used.This is quite advantageous for maximizing the data rate.

With regard to the gain adjustment, note that each endpoint may functionas both a transmitter and a receiver according to one or more duplexingalgorithms. Duplex refers to a point-to-point communication link inwhich both endpoints can communicate with one another in bothdirections. In a full-duplex system, both endpoints can simultaneouslycommunicate with one another. In a half-duplex system, only one endpointcan send information to the other at a time. In a wireless link, afull-duplex channel generally relies on physical isolation of atransmitter and receiver, and suitable interference cancellationtechnologies. Full-duplex emulation is frequently implemented forwireless links by utilizing frequency division duplex (FDD) or timedivision duplex (TDD). In FDD, transmissions in different directionsoperate at different carrier frequencies. In TDD, transmissions indifferent directions on a given channel are separated from one anotherusing time division multiplexing. That is, at one time the channel isdedicated for transmissions in one direction, while at other times thechannel is dedicated for transmissions in the other direction, where thedirection may change periodically or aperiodically.

Some example endpoint architectures and corresponding methods ofoperation will now be discussed. An example endpoint 600 for a lensantenna array system is shown in FIG. 6 . For illustration clarity, theassociated lens for endpoint 600 is not shown in FIG. 6 . Endpoint 600may also be denoted as a network node. In operation, the point-to-pointcommunication between a pair of network nodes 600 may be deemed to bebetween an access point network node and a user terminal network node.Network node 600 is generic to either an access point or a userterminal. Network node 600 includes a processing system 614 having a businterface 608, a bus 602, a memory 605, a processor 604, and acomputer-readable medium 606. Furthermore, node 600 may include a userinterface 612 and a transceiver 610. Transceiver 610 transmits andreceives through an array of antennas 660 as discussed previously withregard to lens antenna array transmitter 101 and lens antenna arrayreceiver 102.

Processor 604 is also responsible for managing the bus 602 and generalprocessing, including the execution of software stored on thecomputer-readable medium 606. The software, when executed by theprocessor 604, causes the processing system 614 to perform the massivebeam communication disclosed herein. The computer-readable medium 606and the memory 605 may also be used for storing data that is manipulatedby the processor 604 when executing software.

The bus 602 may include any number of interconnecting buses and bridgesdepending on the specific application of the processing system 614 andthe overall design constraints. The bus 602 communicatively couplestogether various circuits including one or more processors (representedgenerally by the processor 604), the memory 605, and computer-readablemedia (represented generally by the computer-readable medium 606). Thebus 602 may also link various other circuits such as timing sources,peripherals, voltage regulators, and power management circuits, whichare well known in the art, and therefore, will not be described anyfurther. The bus interface 608 provides an interface between the bus 602and the transceiver 610. The transceiver 610 provides a communicationinterface or means for communicating with various other apparatus over atransmission medium. Depending upon the nature of the apparatus, a userinterface 612 (e.g., keypad, display, speaker, microphone, joystick) mayalso be provided. For each transmitting/receiving link, transceiver 610may include the mixer 310, power amplifier 230, oscillator 325, gaincontroller 330, low-noise amplifier 340, and envelope detector 345discussed with regard to FIG. 3 . Processor 604 may generate thebaseband input data stream for each transmitting link and may receivethe baseband output data stream from each receiving link.

Processor 604 manages the establishment of each communication link and asubsequent optimization of the individual communication link gain. Aflowchart for a method 700 of an initial establishment and optimizationof the communication links is shown in FIG. 7 . Method 700 occursbetween an access point and a user terminal. As defined herein, anaccess point is the network node 600 that initiates the establishment ofthe communication links. After a boot-up of each processor 604 for thetwo network nodes (or a single processor in embodiments in which onlythe access point includes a processor) in a step 705, processor 604 inthe access point initiates a search for the user terminal in a step 710.Prior to this search, processor 604 selects the desired number ofcommunication links to be established. Each link may be implemented by aone-to-one mapping of a transmitting antenna to a receiving antenna.More generally, each link may be implemented by a mapping of a sub-arrayof transmit antennas to a corresponding sub-array of receive antennas.In general, the number of links is limited by the number of transmitantennas that may be driven with a corresponding data stream. Dependingupon the implementation, processor 604 may select some or all of thetransmit antennas. With the transmit antennas selected, the access pointproceeds to test each link. Such a testing may be performed as shown inFIGS. 1A-1C. For example, in FIG. 1A, it is central transmit antenna 110that is activated. If the antenna lens array receiver 103 is properlyaligned with central axis 121, the transmitted RF signal 145 would befocused primarily onto central receive antenna 135. But a misalignmentof antenna lens array receiver 103 (in this example, the user terminal)may result in a focusing of the transmitted RF signal 145 onto adifferent receive antenna. The transmit antenna(s) for eachcommunication link may thus be sequentially (or simultaneously)activated and the resulting focusing onto the receive antennas observed.Processor 604 in the user terminal may thus identify which receiveantennas are being targeted by which communication link as determined bywhether the corresponding received RF signal for the communication linksatisfies a link threshold (S_criteria) in a step 715. For example, thelink threshold may be a power threshold for the received RF signal.Alternatively, the link threshold may comprise a successful decoding ofa message. In other embodiments, the link threshold may be asignal-to-noise ratio (SNR) threshold.

In general, the number of successful links depends upon the alignmentbetween the access point and the user terminal. The link threshold maythus be a minimum number of links that are acceptable. For example,suppose that N links are desired but that some smaller number of linksthan N (e.g., N−X, where X is less than N) would also be acceptable. Thelink threshold could thus be that the number of successful links isgreater than or equal to N−X.

After all the links have been scanned and the link threshold satisfied,the user terminal reports the identity of the successful links to theaccess points in a step 720. Since a priori, it is unknown which linkswill be successfully established, their identification in a step 720 maybe analogized to a random access channel (RACH) message. If the RACH wasdeemed successful with regard to identifying the desired links in a step725, a downlink (DL) measurement stage may ensue. If, however, the RACHwas not successful, the method returns to the access point search step710.

In embodiments in which the gain is not being optimized, a connectedstate would follow a successful RACH step 725 in which the establishedlinks would transmit their data streams. However, in embodiments inwhich the power amplifier gain for the links is adjusted to increase theachievable data rate or to improve the signal quality, method 700continues with a downlink (DL) measurement step 730 following asuccessful RACH step 725. The access point transmits over each link tothe user terminal. The transmission direction on a link from the accesspoint to the user terminal may be deemed to a downlink transmission.Conversely, the transmission direction on a link from the user terminalto the access point may be deemed to be an uplink (UL) transmission. Instep 730, a signal quality is measured for each active downlink link.For example, one measure of signal quality is asignal-to-interference-plus-noise ratio (SINR). Step 730 may thusinvolve the measurement of the SINR at the user terminal for each activedownlink link while the active downlink links are all transmittingsimultaneously.

In contrast to a downlink link, an uplink link transmits data from theuser terminal to the access point. The measurement steps in method 700also includes an uplink signal quality measurement in a step 735 that isanalogous to the downlink signal quality measurement act 730. In step735, the signal quality is measured at the access point for each activeuplink link while the active uplink links are all transmittingsimultaneously. One measure of signal quality is the SINR although othersignal quality measures may be used. In embodiments in which the lensesand the antenna arrays are symmetric at both the transmitting endpointand the receiving endpoint, the uplink link corresponding to a downlinklink will involve the same antennas (or sub-arrays of antennas). Thus,the RACH procedure identifies not only the functioning downlink linksbut also the corresponding uplink links in symmetric implementations.

A signal quality optimization calculation stage follows the linkmeasurement stage. The following discussion will assume that the signalquality is determined by the SINR without loss of generality. The SINRoptimization calculation stage includes an optimization calculation forthe UL links in a step 740. It is convenient for this calculation totake place in the access point since it is the access point thatmeasured the SINR for the active UL links, but it may be performed bythe user terminal in alternative embodiments. Similarly, it isconvenient that a DL link optimization calculation step 745 occurs inthe user terminal, but it may occur in the access point in alternativeembodiments. The optimization calculation may be performed using aformula or may be heuristic. For both the UL and the DL, the calculationdetermines a gain for the power amplifier in the corresponding link.

A link adjustment stage follows the signal quality optimization stage.The link adjustment stage includes an UL beam selection and poweradjustment messaging step 750 in which the access point uses one or moreof the active DL links to transmit the calculated UL gain adjustmentsfor the active UL links to the user terminal. Similarly, the userterminal transmits the calculated DL gain adjustments to the accesspoint in a step 755. With both endpoints having the appropriate gains, aconnected mode of operation may proceed in a step 760 in which theactive DL and UL links transmit data using their power amplifiers 320 attheir adjusted gain.

Although method 700 establishes active UL and DL links with or withoutgain optimization so that a connected mode of operation may ensue, notethat the channel is open space between the lens antenna arraytransmitters and receivers. The movement of personnel and other effectscan thus readily change the channel properties such that what was anactive link becomes degraded. The gain optimization process may thus berepeated as shown for a method 800 in FIG. 8 that occurs during theconnected mode of operation. After the initiation discussed with regardto method 700 is completed in a step 805 such that a connected stateoperation ensues, a periodic (or aperiodic) SINR optimization may beinitiated in a step 810. The subsequent SINR optimization is analogousto as discussed for method 700 and includes a link measurement stagehaving a DL link measurement step 815. In step 815, a signal quality ismeasured for each active downlink. For example, one measure of signalquality is a signal-to-interference-plus-noise ratio (SINR) but othermeasures may be measured and optimized in alternate embodiments. Thelink measurement stage also includes an UL link measurement step 820 inwhich the signal quality such as the SINR is measured for each activeuplink.

An SINR optimization calculation stage follows the link measurementstage analogously as also discussed for FIG. 7 . The SINR optimizationcalculation stage includes an UL link SINR optimization calculation step825. It is convenient for this calculation to take place in the accesspoint since it is the access point that measured the SINR for the activeUL links, but it may be performed by the user terminal in alternativeembodiments. Similarly, it is convenient that a DL link optimizationcalculation step 830 occurs in the user terminal but it may occur in theaccess point in alternative embodiments. The optimization calculationmay be performed using a formula or may be heuristic. For both the ULand the DL, the calculation determines a gain for the power amplifier320 in the corresponding link.

A link adjustment stage following the SINR optimization calculationstage. The link adjustment stage includes an UL beam selection and poweradjustment messaging step 835 in which the access point uses one or moreof the active DL links to transmit the calculated UL gain adjustmentsfor the active UL links to the user terminal. Similarly, the userterminal transmits the calculated DL gain adjustments to the accesspoint in a step 840. With both endpoints having the appropriate gains, aconnected mode of operation may proceed in a step 845 in which theactive DL and UL links transmit data using their power amplifiers 320 atthe adjusted gains. Depending upon the periodicity (or aperiodicity),the SINR optimization repeats by a return to step 810.

As noted earlier, the MCS is not limited to OOK but includes anysuitable modulation. For example, orbital angular momentum (OAM)modulation may be used in alternative implementations. In anOAM-modulated embodiment, multiple layers may be mapped to correspondingsubsets of transmit and receive antennas. Each layer is thus mapped to acorresponding subset of transmit and receive antennas. The power controldiscussed with regard to FIGS. 7 and 8 may thus be adapted to controlthe transmit powers for the various layers in an OAM-modulatedembodiment to maximize the total data rate across the layers. Note thatthe maximization of this data rate by adapting the power need not belimited to producing an acceptable SIR in each link. For example, awater-filling algorithm may be applied to optimize the available poweracross the various layers or data streams disclosed herein.

An example method of wireless communication for a transmitter in a lensantenna array system will now be discussed with regard to the flowchartof FIG. 9 . The method includes an act 900 that occurs at a transmitterincluding an array of transmit antennas arranged in a focal region of atransmit lens and includes amplifying a plurality of first modulated RFsignals through a plurality of power amplifiers according to a defaultgain to produce a corresponding plurality of first amplified modulatedRF signals. The amplification through power amplifiers 320 during eitherof the DL or UL links measurements discussed with regard to FIG. 7 is anexample of act 900. The method further includes an act 905 oftransmitting from each transmit antenna a respective first amplifiedmodulated RF signal from the plurality of first amplified modulated RFsignals to form a plurality of first transmitted RF signals, each firsttransmitted RF signal refracting through the transmit lens andnear-field propagating to a receiver. The transmission of the RF signalsaccording to the default gain levels in either of the DL or UL linksmeasurement discussed with regard to FIG. 7 is an example of act 905. Inaddition, the method includes an act 910 of adjusting the default gainfor each power amplifier responsive to a first signal qualitydetermination for the plurality of first transmitted RF signals to forma plurality of adjusted gain. The UL or DL SINR optimization calculationdiscussed with regard to FIGS. 5 and 7 is an example of act 910.Finally, the method includes an act 915 of amplifying a plurality ofsecond modulated RF signals through the plurality of power amplifiersaccording to the plurality of adjusted gains to produce a correspondingplurality of second amplified modulated RF signals. The UL or DL beamselection and power adjustment discussed with regard to FIG. 7 is anexample of act 915.

Some aspects of the disclosure will now be summarized through thefollowing example clauses:

Clause 1. A lens antenna array system, comprising:

-   -   a first processor configured to provide a plurality of baseband        input data streams;    -   a plurality of modulators corresponding to the plurality of        baseband input data streams, each modulator in the plurality of        modulators configured to modulate a respective baseband input        data stream from the plurality of baseband input data streams to        produce a modulated RF signal;    -   a plurality of power amplifiers corresponding to the plurality        of modulators, each power amplifier configured to amplify a        respective modulator's modulated RF signal according to a gain        to produce an amplified modulated RF signal;    -   a first lens;    -   a plurality of transmit antennas corresponding to the plurality        of power amplifiers, each transmit antenna in the plurality of        transmit antennas being configured to transmit the amplified        modulated RF signal from a respective power amplifier, the        plurality of transmit antennas being arranged in a focal region        of the first lens; and    -   a power controller configured to adjust each gain so that a gain        of a first subset of power amplifiers in the plurality of power        amplifiers is reduced from a default gain level and so that a        gain of a second subset of power amplifiers in the plurality of        power amplifiers is increased from the default gain level.        Clause 2. The lens antenna array system of clause 1, further        comprising:    -   a second lens; and    -   a plurality of receive antennas arranged in a focal region of        the second lens, the first lens being aligned with the second        lens so that each amplified modulated RF signal propagates from        the first lens to the second lens in a near-field regime.        Clause 3. The lens antenna array system of any of clauses 1-2,        wherein each modulator is an on-off keying modulator.        Clause 4. The lens antenna array system of any of clauses 1-2,        wherein each modulator is an orbital angular momentum (OAM)        modulator.        Clause 5. The lens antenna array system of clause 3, further        comprising:    -   a plurality of on-off keying demodulators corresponding to the        plurality of receive antennas, each on-off keying demodulator        being configured to demodulate a received RF signal from its        corresponding receive antenna.        Clause 6. The lens antenna array system of any of clauses 2, 4,        and 5, wherein the second lens is substantially similar to the        first lens.        Clause 7. The lens antenna array system of any of clauses 2, 4,        5, and 6, wherein a central axis of the first lens is        substantially aligned with a central axis of the second lens.        Clause 8. The lens antenna array system of clause 3, wherein the        first processor is further configured to sequentially activate        each on-off keying modulator during an acquisition period;    -   a second processor configured to determine a mapping between        each transmit antenna and each receive antenna responsive to a        sequential activation of each on-off keying modulator.        Clause 9. The lens antenna array system of clause 7, wherein the        first subset of power amplifiers correspond to a first subset of        transmit antennas in the plurality of transmit antennas and the        second subset of power amplifiers correspond to a second subset        of transmit antennas in the plurality of transmit antennas, and        wherein the first subset of transmit antennas are arranged in a        central portion of the focal region of the first lens, and        wherein the second subset of transmit antennas are arranged in a        peripheral portion of the focal region of the first lens.        Clause 10. The lens antenna array system of clause 9, wherein        the central portion of the focal region of the first lens is        aligned with the central axis of the first lens.        Clause 11. A method of wireless communication, comprising:    -   at a transmitter including an array of transmit antennas        arranged in a focal region of a transmit lens, amplifying a        plurality of first modulated RF signals through a plurality of        power amplifiers according to a default gain to produce a        corresponding plurality of first amplified modulated RF signals;    -   transmitting from each transmit antenna a respective first        amplified modulated RF signal from the plurality of first        amplified modulated RF signals to form a plurality of first        transmitted RF signals, each first transmitted RF signal        refracting through the transmit lens and near-field propagating        to a receiver;    -   adjusting the default gain for each power amplifier responsive        to a first signal quality determination for the plurality of        first transmitted RF signals to form a plurality of adjusted        gains; and    -   amplifying a plurality of second modulated RF signals through        the plurality of power amplifiers according to the plurality of        adjusted gains to produce a corresponding plurality of second        amplified modulated RF signals.        Clause 12. The method of clause 11, further comprising:

transmitting from each transmit antenna a respective second amplifiedmodulated RF signal from the plurality of second amplified modulated RFsignals to form a plurality of second transmitted RF signals, eachsecond transmitted RF signal refracting through the transmit lens andnear-field propagating to the receiver.

Clause 13. The method of clause 12, further comprising:

-   -   at the transmitter, receiving a second signal quality        determination for each second amplified modulated RF signal in        the plurality of second amplified modulated RF signals, wherein        the first signal quality determination includes at least one        unacceptable signal quality and the wherein the second signal        quality determination includes no unacceptable signal quality.        Clause 14. The method of clause 13, wherein forming the first        signal quality determination and forming the second signal        quality determination both comprise forming a        signal-to-interference-ratio (SINR).        Clause 15. The method of clause 14, wherein the at least one        unacceptable signal quality comprises an SINR that is less than        an acceptable level.        Clause 16. The method of any of clause 11-15, wherein adjusting        the default gain for each power amplifier responsive to the        first signal quality determination to form the plurality of        adjusted gains decreases a gain for a first subset of power        amplifiers from the default gain and increases a gain for a        second subset of power amplifiers from the default gain.        Clause 17. The method of any of clauses 11-16, further        comprising:    -   producing a plurality of baseband input data streams; and    -   modulating an RF signal responsive to each baseband input data        stream to form the plurality of first modulated RF signals.        Clause 18. The method of clause 17, wherein modulating the RF        signal responsive to each baseband input data stream comprises        modulating the RF signal according to an on-off keying        modulation responsive to each baseband input data stream.        Clause 19. A method of wireless communication, comprising:    -   in a lens antenna system including a receiver having an array of        receive antennas arranged in a focal region of a second lens,        receiving at each receive antenna a first RF signal that        near-field propagated from a transmitter to form a plurality of        first received RF signals;    -   at the receiver, forming a plurality of first signal quality        determinations corresponding to the plurality of first received        RF signals; and    -   reporting the plurality of first signal quality determinations        to the transmitter.        Clause 20. The method of clause 19, further comprising:    -   at the receiver, receiving at each receive antenna a second RF        signal that near-field propagated from the transmitter to form a        plurality of second received RF signals; and    -   at the receiver, forming a plurality of second signal quality        determinations corresponding to the plurality of second received        RF signals, wherein the plurality of first signal quality        determinations includes at least one unacceptable signal quality        and the wherein the plurality of second signal quality        determinations includes no unacceptable signal quality.        Clause 21. The method of clause 20, wherein each first signal        quality determination in the plurality of first signal quality        determinations comprises a signal-to-interference ratio (SINR)        and wherein each second signal quality determination in the        plurality of second signal quality determinations comprises an        SINR.        Clause 22. The method of clause 21, wherein the at least one        unacceptable signal quality comprises an SINR that is less than        an acceptable level.        Clause 23. The method of any of clauses 21 and 22, further        comprising:    -   demodulating each second received RF signal in the plurality of        second received RF signals to form a plurality of received        baseband data streams.        Clause 24. The method of any of clauses 21-23, wherein        demodulating each second received RF signal comprises an on-off        keying demodulation.        Clause 25. A method of wireless communication, comprising:    -   in a lens antenna array system including a transmitter and a        receiver, near-field propagating from a transmit lens in the        transmitter to the receiver a plurality of first amplified RF        signals;    -   at the transmitter, receiving from the receiver a signal quality        determination for the plurality of first amplified RF signals;        and    -   adjusting a plurality of gains for a plurality of power        amplifiers in the transmitter responsive to the signal quality        determination.        Clause 26. The method of clause 25, wherein the adjusting of the        plurality of gains improves a signal quality for a plurality of        second amplified RF signals that near-field propagate from the        transmit lens in the transmitter to the receiver.        Clause 27. The method of any of clauses 25 and 26, wherein the        adjusting the plurality of gains comprises adjusting the        plurality of gains from a default level used to amplify the        plurality of first amplified RF signals.        Clause 28. The method of clause 27, wherein adjusting the        plurality of gains comprises increasing a first subset of gains        in the plurality of gains from the default level and further        comprises decreasing a second subset of gains in the plurality        of gains from the default level.

In various implementations, lens antenna array systems disclosed hereinmay utilize licensed spectrum, unlicensed spectrum, or shared spectrum.Licensed spectrum provides for exclusive use of a portion of thespectrum, generally by virtue of a mobile network operator purchasing alicense from a government regulatory body. Unlicensed spectrum providesfor shared use of a portion of the spectrum without need for agovernment-granted license. While compliance with some technical rulesis generally still required to access unlicensed spectrum, generally,any operator or device may gain access. Shared spectrum may fall betweenlicensed and unlicensed spectrum, wherein technical rules or limitationsmay be required to access the spectrum, but the spectrum may still beshared by multiple operators and/or multiple lens antenna array systems.For example, the holder of a license for a portion of licensed spectrummay provide licensed shared access (LSA) to share that spectrum withother parties, e.g., with suitable licensee-determined conditions togain access.

Several aspects of a wireless communication network have been presentedwith reference to an exemplary implementation. As those skilled in theart will readily appreciate, various aspects described throughout thisdisclosure may be extended to other telecommunication systems, networkarchitectures and communication standards.

By way of example, various aspects may be implemented within othersystems defined by 3GPP, such as Long-Term Evolution (LTE), the EvolvedPacket System (EPS), the Universal Mobile Telecommunication System(UMTS), and/or the Global System for Mobile (GSM). Various aspects mayalso be extended to systems defined by the 3rd Generation PartnershipProject 2 (3GPP2), such as CDMA2000 and/or Evolution-Data Optimized(EV-DO). Other examples may be implemented within systems employing IEEE802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Ultra-Wideband (UWB),Bluetooth, and/or other suitable systems. The actual telecommunicationstandard, network architecture, and/or communication standard employedwill depend on the specific application and the overall designconstraints imposed on the system.

Within the present disclosure, the word “exemplary” is used to mean“serving as an example, instance, or illustration.” Any implementationor aspect described herein as “exemplary” is not necessarily to beconstrued as preferred or advantageous over other aspects of thedisclosure. Likewise, the term “aspects” does not require that allaspects of the disclosure include the discussed feature, advantage ormode of operation. The term “coupled” is used herein to refer to thedirect or indirect coupling between two objects. For example, if objectA physically touches object B, and object B touches object C, thenobjects A and C may still be considered coupled to one another—even ifthey do not directly physically touch each other. For instance, a firstobject may be coupled to a second object even though the first object isnever directly physically in contact with the second object. The terms“circuit” and “circuitry” are used broadly, and intended to include bothhardware implementations of electrical devices and conductors that, whenconnected and configured, enable the performance of the functionsdescribed in the present disclosure, without limitation as to the typeof electronic circuits, as well as software implementations ofinformation and instructions that, when executed by a processor, enablethe performance of the functions described in the present disclosure.

One or more of the components, steps, features and/or functionsillustrated herein may be rearranged and/or combined into a singlecomponent, step, feature or function or embodied in several components,steps, or functions. Additional elements, components, steps, and/orfunctions may also be added without departing from novel featuresdisclosed herein. The apparatus, devices, and/or components illustratedherein may be configured to perform one or more of the methods,features, or steps escribed herein. The novel algorithms describedherein may also be efficiently implemented in software and/or embeddedin hardware.

It is to be understood that the specific order or hierarchy of steps inthe methods disclosed is an illustration of exemplary processes. Basedupon design preferences, it is understood that the specific order orhierarchy of steps in the methods may be rearranged. The accompanyingmethod claims present elements of the various steps in a sample orderand are not meant to be limited to the specific order or hierarchypresented unless specifically recited therein.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein but are to be accorded the full scope consistentwith the language of the claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. A phrase referring to“at least one of” a list of items refers to any combination of thoseitems, including single members. As an example, “at least one of: a, b,or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, band c. All structural and functional equivalents to the elements of thevarious aspects described throughout this disclosure that are known orlater come to be known to those of ordinary skill in the art areexpressly incorporated herein by reference and are intended to beencompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims. No claim element is tobe construed under the provisions of 35 U.S.C. § 112(f) unless theelement is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.”

What is claimed is:
 1. A lens antenna array system, comprising: a firstprocessor configured to provide a plurality of baseband input datastreams; a plurality of modulators corresponding to the plurality ofbaseband input data streams, each modulator in the plurality ofmodulators configured to modulate a respective baseband input datastream from the plurality of baseband input data streams to produce amodulated RF signal; a plurality of power amplifiers corresponding tothe plurality of modulators, each power amplifier configured to amplifya respective modulator's modulated RF signal according to a gain toproduce an amplified modulated RF signal; a first lens; a plurality oftransmit antennas corresponding to the plurality of power amplifiers,each transmit antenna in the plurality of transmit antennas beingconfigured to transmit the amplified modulated RF signal from arespective power amplifier, the plurality of transmit antennas beingarranged in a focal region of the first lens; and a power controllerconfigured to adjust each gain so that a gain of a first subset of poweramplifiers in the plurality of power amplifiers is reduced from adefault gain level and so that a gain of a second subset of poweramplifiers in the plurality of power amplifiers is increased from thedefault gain level.
 2. The lens antenna array system of claim 1, furthercomprising: a second lens; and a plurality of receive antennas arrangedin a focal region of the second lens, the first lens being aligned withthe second lens so that each amplified modulated RF signal propagatesfrom the first lens to the second lens in a near-field regime.
 3. Thelens antenna array system of claim 2, wherein each modulator is anon-off keying modulator.
 4. The lens antenna array system of claim 2,wherein each modulator is an orbital angular momentum (OAM) modulator.5. The lens antenna array system of claim 3, further comprising: aplurality of on-off keying demodulators corresponding to the pluralityof receive antennas, each on-off keying demodulator being configured todemodulate a received RF signal from its corresponding receive antenna.6. The lens antenna array system of claim 3, wherein the second lens issubstantially similar to the first lens.
 7. The lens antenna arraysystem of claim 2, wherein a central axis of the first lens issubstantially aligned with a central axis of the second lens.
 8. Thelens antenna array system of claim 3, wherein the first processor isfurther configured to sequentially activate each on-off keying modulatorduring an acquisition period; a second processor configured to determinea mapping between each transmit antenna and each receive antennaresponsive to a sequential activation of each on-off keying modulator.9. The lens antenna array system of claim 7, wherein the first subset ofpower amplifiers correspond to a first subset of transmit antennas inthe plurality of transmit antennas and the second subset of poweramplifiers correspond to a second subset of transmit antennas in theplurality of transmit antennas, and wherein the first subset of transmitantennas are arranged in a central portion of the focal region of thefirst lens, and wherein the second subset of transmit antennas arearranged in a peripheral portion of the focal region of the first lens.10. The lens antenna array system of claim 9, wherein the centralportion of the focal region of the first lens is aligned with thecentral axis of the first lens.
 11. A method of wireless communication,comprising: in a lens antenna array system including a transmitter and areceiver, near-field propagating from a transmit lens in the transmitterto the receiver a plurality of first amplified RF signals; at thetransmitter, receiving from the receiver a signal quality determinationfor the plurality of first amplified RF signals; and adjusting aplurality of gains for a plurality of power amplifiers in thetransmitter responsive to the signal quality determination, wherein theadjusting the plurality of gains comprises increasing a first subset ofgains in the plurality of gains from the default level and furthercomprises decreasing a second subset of gains in the plurality of gainsfrom the default level.
 12. The method of claim 11, wherein theadjusting of the plurality of gains improves a signal quality for aplurality of second amplified RF signals that near-field propagate fromthe transmit lens in the transmitter to the receiver.
 13. The method ofclaim 11, wherein the adjusting the plurality of gains comprisesadjusting the plurality of gains from a default level used to amplifythe plurality of first amplified RF signals.
 14. The method of claim 11,further comprising: modulating a plurality of RF signals according to anon/off keying modulation to form a plurality of modulated RF signals;and amplifying the modulated RF signals to form the plurality of firstamplified RF signals.
 15. The method of claim 11, further comprising:modulating a plurality of RF signals according to an orbital angularmomentum modulation to form a plurality of modulated RF signals; andamplifying the modulated RF signals to form the plurality of firstamplified RF signals.